electrophileblocking

Electrophile blocking is a technique used in organic chemistry to prevent unwanted reactions involving electrophilic species. Electrophiles are electron-deficient atoms or molecules that tend to accept electrons, often participating in reactions such as alkylation or acylation. In some synthetic strategies, it is necessary to temporarily deactivate a particular site in a molecule that would otherwise be susceptible to electrophilic attack. This is achieved by introducing a "blocking group" that sterically hinders or electronically modifies the reactive site, making it less accessible or less attractive to electrophiles.

Common electrophile blocking groups include bulky substituents that physically prevent the approach of an electrophile. Alternatively, electron-donating groups can be temporarily attached to a position that would normally be electrophilic, thereby increasing its electron density and reducing its reactivity towards incoming electrophiles. After the desired reactions have been carried out elsewhere in the molecule, the blocking group is removed under specific conditions, restoring the original functionality and allowing for subsequent reactions to occur at that site. This strategy is particularly useful in the synthesis of complex molecules where selective functionalization is crucial.